Over 6,000 years, corn has changed


BELTSVILLE, Md. – Those ears of sweet, crisp corn that are such a familiar part of summertime picnics haven’t always looked or tasted that way.
Rather, this staple veggie – and its genes – have been tweaked over time by thousands of generations of humans hoping to harvest a better crop.
Impacts. Now, an Agricultural Research Service geneticist and his colleagues from across the country have discovered what impact all those years of preferential planting have had on corn’s genetic makeup.
Michael McMullen, a geneticist in the service’s Plant Genetics Research Unit at Columbia, Mo., worked with researchers from the University of California-Irvine, the University of Missouri and the University of Wisconsin to discover which genes play a role in making corn the important food and animal feed source it is today.
Teosinte. It’s generally believed that corn was domesticated from its wild relative, teosinte, some 6,000-9,000 years ago in Mexico.
A wild grass, teosinte doesn’t look much like corn; it even lacks the “ears” that make corn plants so recognizable.
Corn genes. The researchers discovered that humans, starting with ancient Americans to present-day growers, have impacted about 2 percent to 4 percent of corn’s genes in their quest for a better-tasting and more cultivable corn crop.
The scientists believe the affected genes are most likely linked to qualities like growth and yield.
Their work has many implications, including establishing an approach for studying the genetics of domestication of other crops and animals.
Still remains. The research shows a large amount of genetic diversity still remains for the vast majority of corn’s genes – enabling future corn improvement by plant breeders.
It also noted that knowing the 2 percent to 4 percent currently lacking genetic variation will help plant geneticists use wild and exotic corn varieties to continually improve this important crop.


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